Ablation catheter

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No. 13/677,571, filed Nov. 15, 2012, now issued U.S. Pat. No. 8,771,267, entitled ABLATION CATHETER, which is a continuation of U.S. patent application Ser. No. 12/938,791, filed Nov. 3, 2010, entitled ABLATION CATHETER, now issued U.S. Pat. No. 8,337,492, issued Dec. 25, 2012, which is a continuation of U.S. patent application Ser. No. 11/471,467, filed Jun. 20, 2006, entitled ABLATION CATHETER, now issued U.S. Pat. No. 7,850,685, issued Dec. 14, 2010, which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/692,416, filed Jun. 20, 2005, the entirety of which is incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

N/A

FIELD OF THE INVENTION

The present invention relates generally to catheters and methods for performing targeted tissue ablation in a subject. In particular, the present invention provides devices comprising catheters having distal ends configured to pulmonary vein ostia, and methods for treating conditions (e.g., cardiac arrhythmias) with these and similar devices.

BACKGROUND OF THE INVENTION

Tissue ablation is used in numerous medical procedures to treat a patient. Ablation can be performed to remove undesired tissue such as cancer cells. Ablation procedures may also involve the modification of the tissue without removal, such as to stop electrical propagation through the tissue in patients with an arrhythmia. Often the ablation is performed by passing energy, such as electrical energy, through one or more electrodes causing the tissue in contact with the electrodes to heats up to an ablative temperature. Ablation procedures can be performed on patients with atrial fibrillation by ablating tissue in the heart.

Mammalian organ function typically occurs through the transmission of electrical impulses from one tissue to another. A disturbance of such electrical transmission may lead to organ malfunction. One particular area where electrical impulse transmission is critical for proper organ function is in the heart. Normal sinus rhythm of the heart begins with the sinus node generating an electrical impulse that is propagated uniformly across the right and left atria to the atrioventricular node. Atrial contraction leads to the pumping of blood into the ventricles in a manner synchronous with the pulse.

Atrial fibrillation refers to a type of cardiac arrhythmia where there is disorganized electrical conduction in the atria causing rapid uncoordinated contractions that result in ineffective pumping of blood into the ventricle and a lack of synchrony. During atrial fibrillation, the atrioventricular node receives electrical impulses from numerous locations throughout the atria instead of only from the sinus node. This overwhelms the atrioventricular node into producing an irregular and rapid heartbeat. As a result, blood pools in the atria that increases a risk for blood clot formation. The major risk factors for atrial fibrillation include age, coronary artery disease, rheumatic heart disease, hypertension, diabetes, and thyrotoxicosis. Atrial fibrillation affects 7% of the population over age 65.

Atrial fibrillation treatment options are limited. Lifestyle change only assists individuals with lifestyle related atrial fibrillation. Medication therapy assists only in the management of atrial fibrillation symptoms, may present side effects more dangerous than atrial fibrillation, and fail to cure atrial fibrillation. Electrical cardioversion often restores sinus rhythm, but has a high recurrence rate. In addition, if there is a blood clot in the atria, cardioversion may cause the clot to leave the heart and travel to the brain or to some other part of the body, which may lead to stroke. What are needed are new methods for treating atrial fibrillation and other conditions involving disorganized electrical conduction.

Various ablation techniques have been proposed to treat atrial fibrillation, including the Cox-Maze procedure, linear ablation of various regions of the atrium, and circumferential ablation of pulmonary vein ostia. The Cox-Maze procedure and linear ablation procedures are tedious and time-consuming, taking several hours to accomplish. Pulmonary vein ostial ablation is proving to be difficult to do, and has resulted in inadequate results and unacceptable trauma to the pulmonary veins. There is therefore a need for improved atrial ablation products and techniques.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, an ablation catheter for an operator to treat a patient with an arrhythmia is disclosed. The catheter includes an elongate, flexible tubular body member have a proximal end, a distal end and a lumen therebetween. The catheter further includes a control shaft, coaxially disposed and slidingly received with the lumen of the tubular body member. A flexible carrier assembly is attached to the end of the control shaft and includes at least one ablation and/or mapping elements. Retraction of the control shaft causes the carrier assembly to transition from a compact, near linear configuration, to a helix or partial helix. In a preferred embodiment, the helix is less than 360°.

In a preferred embodiment, the carrier assembly can be withdrawn into a location within the tubular body member. In another preferred embodiment, the ablation catheter includes at least two carrier assemblies that can be transitioned between a compact, near linear configuration to a helix or partial helix. In yet another preferred embodiment, the catheter can be placed over a guidewire or includes an integral guidewire tip.

According to another aspect of the invention, an ablation catheter for an operator to treat a patient with an arrhythmia is disclosed. The catheter includes an elongate, flexible tubular body member have a proximal end, a distal end and a lumen therebetween. The catheter further includes a control shaft, coaxially disposed and slidingly received with the lumen of the tubular body member. A flexible carrier assembly is attached to the end of the control shaft and includes at least one ablation and/or mapping elements in an umbrella tip configuration. Retraction of the control shaft causes the carrier assembly to change shape, such as to conform to tissue surrounding one or more pulmonary veins entering the left atrium of a patient.

In a preferred embodiment, the ablation catheter includes a second carrier assembly, also in an umbrella tip configuration. In another preferred embodiment, the catheter includes an anchoring element, such as a balloon or expandable cage, for stabilizing and/or anchoring the ablation catheter in a pulmonary vein. In yet another preferred embodiment, the catheter includes an ultrasound element for directing ultrasound energy in a circular pattern toward tissue. In yet another preferred embodiment, one or more carrier arms of the umbrella tip can be rotated, stabilized, or otherwise manipulated to better conform to or stabilize with tissue such as pulmonary vein ostial tissue. In yet another preferred embodiment, the catheter can be placed over a guidewire or includes an integral guidewire tip. In yet another preferred embodiment, the catheter includes an advancable spline which can be used to position or stabilize the carrier assembly.

According to yet another aspect of the invention, an ablation catheter for an operator to treat a patient with an arrhythmia is disclosed. The catheter includes an elongate, flexible tubular body member have a proximal end, a distal end and a lumen therebetween. The catheter further includes a flexible carrier assembly comprising an inflatable balloon with mounted or embedded ablation and/or mapping elements.

One such example of a minimally invasive therapy involves the treatment of cardiac arrhythmias or irregular heartbeats in which physicians employ specialized cardiac assessment and treatment devices, such as mapping catheters and ablation catheters, to gain access to, diagnose, and treat interior regions of a patient's body. Such devices may include energized electrodes or other ablation assemblies to create lesions or other anatomical effects that disrupt or block electrical pathways through the targeted tissue.

In the treatment of cardiac arrhythmias, a specific area of cardiac tissue having aberrant electrically conductive pathways is typically initially identified for subsequent treatment. This localization or identification can include first using a medical device such as a mapping catheter to obtain a baseline electrophysiological map of electrical activity in selected tissue. After mapping and diagnosing aberrant tissue, a physician may decide to treat the patient by ablating the tissue. An ablation procedure may involve creating one or more lesions to electrically isolate tissue believed to be the source of an arrhythmia. One type of ablation is the cryotreatment or cryogenic ablation, which entails creating cold temperatures at specific regions of the body or contacting tissue with cold treatment devices to transfer heat from the targeted tissue to the cryogenic element, thus cooling and/or ablating the tissue.

Such cryotreatment may require first repositioning or removing a mapping catheter before placing a second medical device or ablation catheter into contact with the tissue to be treated. Following the ablation procedure, the physician may desire to assess or confirm the efficacy of the treatment by obtaining a second electrophysiological map of the tissue region. This subsequent mapping procedure may involve removal or manipulation of the ablation medical device to allow the desired positioning of the mapping device adjacent to the tissue that was previously treated.

Each device exchange or manipulation represents an added risk to the patient as inserting and removing catheters in the vasculature carries a number of inherent risks, possibly including embolism. Exchanging these various catheters during a procedure can cause inaccuracies or movement in the placement and location of the distal tip a device with respect to the tissue to be mapped or ablated, and may further add to the time required to perform the desired treatment. These potential inaccuracies and extended duration of the particular procedure further increase the risk to the patient undergoing treatment. Accordingly, it would be desirable to provide an integrated apparatus and method of use thereof for both diagnosing aberrant electrical pathways and treating those detected pathways.

In addition, placing and maintaining a medical device in the desired position with correct alignment and positive contact with the selected tissue may enhance a mapping and ablation treatment and its likelihood of success. It is therefore desirable to provide apparatus and method of use to verify the position of a medical device, positive contact and alignment with the selected tissue, and to evaluate the medical treatment contemporaneously.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various embodiments of the present invention, and, together with the description, serve to explain the principles of the invention. In the drawings:

<figref idref="DRAWINGS">FIG. 1</figref> illustrates a side sectional view of an ablation catheter, consistent with present invention, with the distal end inserted into a pulmonary vein of a patient;

<figref idref="DRAWINGS">FIGS. 2</figref><i>a </i>and <b>2</b><i>b </i>illustrates a perspective view of the distal portion of the ablation catheter of <figref idref="DRAWINGS">FIG. 1</figref>, consistent with the present invention;

<figref idref="DRAWINGS">FIG. 3</figref> illustrates a perspective view of the distal portion of an ablation catheter consistent with the present invention, in which the device includes a proximal energy delivering carrier assembly and a distal mapping carrier assembly;

<figref idref="DRAWINGS">FIG. 4</figref> illustrates an ablation catheter handle consistent with the present invention including the dual carrier assemblies of <figref idref="DRAWINGS">FIG. 3</figref>;

<figref idref="DRAWINGS">FIG. 5</figref> illustrates a side sectional view of an ablation catheter, consistent with present invention, with the distal end inserted into a pulmonary vein of a patient;

<figref idref="DRAWINGS">FIG. 6</figref> illustrates a perspective view of the distal portion of an ablation catheter consistent with the present invention, in which the carrier assembly includes one or more carrier arms that can be rotationally positioned;

<figref idref="DRAWINGS">FIG. 7</figref> illustrates a perspective view of the distal portion of an ablation catheter consistent with the present invention, in which a sleeve can be advanced to manipulate one or more carrier arms of the carrier assembly, and the distal end includes a flexible wire for inserting into a pulmonary vein;

<figref idref="DRAWINGS">FIG. 8</figref><i>a </i>illustrates a perspective view of the distal portion of an ablation catheter consistent with the present invention, in which one or more carrier arms of the carrier assembly are maintained in close proximity with a collar;

<figref idref="DRAWINGS">FIG. 8</figref><i>b </i>is an end view of the ablation catheter of <figref idref="DRAWINGS">FIG. 8</figref><i>a; </i>

<figref idref="DRAWINGS">FIG. 8</figref><i>c </i>is an end view of the collar of the ablation catheter of <figref idref="DRAWINGS">FIG. 8</figref><i>a; </i>

<figref idref="DRAWINGS">FIG. 9</figref> illustrates a perspective view of the distal portion of an ablation catheter consistent with the present invention, in which the carrier assembly includes a radially deployable spline that can be deployed in between two carrier arms;

<figref idref="DRAWINGS">FIGS. 9</figref><i>a </i>and <b>9</b><i>b </i>illustrate a side view of the distal portion of the ablation catheter of <figref idref="DRAWINGS">FIG. 9</figref><i>a</i>, with the spline in partially and fully deployed conditions, respectively, with the carrier arms removed for clarity;

<figref idref="DRAWINGS">FIG. 10</figref> illustrates a perspective view of the distal portion of an ablation catheter consistent with the present invention, in which the carrier assembly comprises a balloon with fixedly mounted ablation elements;

<figref idref="DRAWINGS">FIG. 11</figref> illustrates a side view of the distal portion of the ablation catheter of <figref idref="DRAWINGS">FIG. 10</figref>;

<figref idref="DRAWINGS">FIG. 12</figref><i>a </i>illustrates a perspective view of an ablation catheter consistent with the present invention, wherein the carrier assembly comprises a single carrier arm and the carrier assembly is in the deployed state;

<figref idref="DRAWINGS">FIG. 12</figref><i>b </i>illustrates a perspective view of a distal portion of the ablation catheter of <figref idref="DRAWINGS">FIG. 12</figref><i>a</i>, in which the carrier assembly is in a fully compacted state;

<figref idref="DRAWINGS">FIG. 12</figref><i>c </i>illustrates a perspective view of a distal portion of the ablation catheter of <figref idref="DRAWINGS">FIG. 12</figref><i>b</i>, in which the carrier assembly is in a partially deployed state;

<figref idref="DRAWINGS">FIG. 13</figref> illustrates a distal portion of an ablation catheter consistent with the present invention, in which the carrier assembly comprises a single carrier arm whose distal end is attached along a different axis than the proximal end;

<figref idref="DRAWINGS">FIG. 13</figref><i>a </i>illustrates a side view of a distal portion of the catheter of <figref idref="DRAWINGS">FIG. 13</figref>;

<figref idref="DRAWINGS">FIG. 13</figref><i>b </i>illustrates a perspective view of a distal portion of the catheter of <figref idref="DRAWINGS">FIG. 13</figref>;

<figref idref="DRAWINGS">FIG. 14</figref> illustrates a side sectional view of a distal portion of an ablation catheter consistent with the present invention, in which the carrier assembly comprises a single carrier arm;

<figref idref="DRAWINGS">FIG. 15</figref><i>a </i>illustrates a perspective view of a proximal portion of an ablation catheter consistent with the present invention, including a handle with multiple controls;

<figref idref="DRAWINGS">FIG. 15</figref><i>b </i>illustrates a perspective view of a distal portion of the ablation catheter of <figref idref="DRAWINGS">FIG. 15</figref><i>a</i>, in which the carrier assembly comprises a single carrier arm and the carrier assembly is in a fully compacted state;

<figref idref="DRAWINGS">FIG. 15</figref><i>c </i>illustrates a perspective view of a distal portion of the ablation catheter of <figref idref="DRAWINGS">FIG. 15</figref><i>a</i>, in which the carrier assembly comprises a single carrier arm and the carrier assembly is in the fully deployed state;

<figref idref="DRAWINGS">FIG. 15</figref><i>d </i>illustrates the ablation catheter of <figref idref="DRAWINGS">FIGS. 15</figref><i>a </i>through <b>15</b><i>c </i>after having been placed through a transeptal sheath and the carrier assembly deployed and contacting the ostium of the left superior pulmonary vein;

<figref idref="DRAWINGS">FIG. 16</figref> illustrates a perspective view of an ablation catheter consistent with the present invention, including a first deployable carrier assembly and a second deployable carrier assembly;

<figref idref="DRAWINGS">FIG. 16</figref><i>a </i>illustrates an end view of the ablation catheter of <figref idref="DRAWINGS">FIG. 16</figref>;

<figref idref="DRAWINGS">FIG. 16</figref><i>b </i>illustrates a side sectional view of the distal portion of the ablation catheter of <figref idref="DRAWINGS">FIG. 16</figref>, wherein the distal carrier assembly is in contact with the lumen of a pulmonary vein and the proximal carrier assembly is in contact with the pulmonary vein ostium;

<figref idref="DRAWINGS">FIG. 17</figref> illustrates a side view of an ablation catheter consistent with the present invention, including a carrier assembly comprising a single carrier arm that can be fully retracted within a lumen of the shaft of the device;

<figref idref="DRAWINGS">FIG. 17</figref><i>a </i>illustrates a side sectional view of the device of <figref idref="DRAWINGS">FIG. 17</figref> wherein the carrier assembly has been fully deployed;

<figref idref="DRAWINGS">FIG. 17</figref><i>b </i>illustrates a side sectional view of the device of <figref idref="DRAWINGS">FIG. 17</figref> wherein the carrier assembly has been fully compacted; and

<figref idref="DRAWINGS">FIG. 17</figref><i>c </i>illustrates an end view of the device of <figref idref="DRAWINGS">FIG. 17</figref><i>a. </i>

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

The present invention provides catheters for performing targeted tissue ablation in a subject. In preferred embodiments, the catheters comprise a tubular body member having a proximal end and distal end and preferably a lumen extending therebetween. The catheter is preferably of the type used for performing intracardiac procedures, typically being percutaneously introduced and advanced from the femoral vein in a patient's leg. Alternative methods involve percutaneous introduction into the jugular vein of the patient's neck, or other anatomical entry point that can be used to access the target location within the patient. The catheter is preferably introduceable through a sheath and also preferably is advancable over a guidewire. The catheter preferably has a steerable tip that allows precise positioning of the distal portion such as when the distal end of the catheter needs to access a pulmonary vein of the left atrium of the patient's heart. The catheters include ablation elements mounted on one or more carrier arms of a flexible carrier assembly. Typical metals chosen for carrier assembly construction include but are not limited to: stainless steel, Nitinol, Elgiloy™, other alloys and combinations thereof. These ablation elements can be used to ablate and/or map electrical activity of tissue. The carrier assembly is attached to a control shaft that is coaxially disposed and slidingly received within the lumen of the tubular body member. The shape of the carrier assembly is adjusted by advancing or retracting the control shaft, such as to engage one or more ablation elements against cardiac tissue, typically pulmonary vein ostial tissue.

Arrays of ablation elements, preferably geometrically-adjustable electrode arrays, may be configured in a wide variety of ways and patterns. In particular, the present invention provides devices with multi-dimensional electrode arrays that provide electrical energy, such as radiofrequency (RF) energy, in monopolar (unipolar), bipolar or combined monopolar-bipolar fashion, as well as methods for treating conditions (e.g., atrial fibrillation, supra ventricular tachycardia, atrial tachycardia, ventricular tachycardia, ventricular fibrillation, and the like) with these devices. Alternative to or in combination with ablation elements that deliver electrical energy to tissue, other forms and types of energy can be delivered including but not limited to: sound energy such as acoustic energy and ultrasound energy; electromagnetic energy such as electrical, magnetic, microwave and radiofrequency energies; thermal energy such as heat and cryogenic energies; chemical energy such as energy generated by delivery of a drug; light energy such as infrared and visible light energies; mechanical and physical energy; radiation; and combinations thereof.

As described above, the normal functioning of the heart relies on proper electrical impulse generation and transmission. In certain heart diseases (e.g., atrial fibrillation) proper electrical generation and transmission are disrupted or are otherwise abnormal. In order to diagnose and/or prevent improper impulse generation and transmission from causing an undesired condition, the ablation catheters of the present invention may be employed.

One current method of treating cardiac arrhythmias is with catheter ablation therapy. Physicians make use of catheters to gain access into interior regions of the body. Catheters with attached electrode arrays or other ablating devices are used to create lesions that disrupt electrical pathways in cardiac tissue. In the treatment of cardiac arrhythmias, a specific area of cardiac tissue having aberrant conductive pathways, such as atrial rotors, emitting or conducting erratic electrical impulses, is initially localized. A user (e.g., a physician) directs a catheter through a main vein or artery into the interior region of the heart that is to be treated. The ablating element or elements are next placed near the targeted cardiac tissue that is to be ablated, such as a pulmonary vein ostium. After performing an electrical mapping procedure, the physician directs energy, provided by a source external to the patient, from one or more ablation elements to ablate the neighboring tissue and form a lesion. In general, the goal of catheter ablation therapy is to disrupt the electrical pathways in cardiac tissue to stop the emission of and/or prevent the propagation of erratic electric impulses, thereby curing the heart of the disorder. For treatment of atrial fibrillation, currently available methods and devices have shown only limited success and/or employ devices that are extremely difficult to use or otherwise impractical.

The ablation catheters of the present invention allow the generation of lesions of appropriate size and shape to treat conditions involving disorganized electrical conduction (e.g., atrial fibrillation). The created lesions are segmented and localized. The lesions may be linear or curvilinear, circumferential and partial circumferential, and/or continuous or discontinuous. The ablation catheters of the present invention are also practical in terms of ease-of-use and limiting risk to the patient, as well as significantly reducing procedure times. The lesions created by the ablation catheters are suitable for inhibiting the propagation of inappropriate electrical impulses in the heart for prevention of reentrant arrhythmias.

The catheters of the present invention can perform tissue ablation and/or mapping of electrical signals present in tissue. Patients, such as those with atrial fibrillation, are diagnosed and treated with the herein described mapping and/or ablation procedures. The catheters of the present invention are specifically applicable to mapping and ablation of the pulmonary vein ostia located in the left atrium of the patient's heart. These vein ostia are approximately 1.5 cm in diameter and often are non-circular in geometry, especially when a venous bifurcation is present proximate the ostia. The carrier assembly of the present invention may include one or more carrier arms that are configured to conform to these circular and non-circular contours of pulmonary vein ostia. One or more carrier arms, or groups of carrier arms, may be configured to be independently advancable and retractable, such as to properly engage pulmonary vein ostium tissue. The carrier arms are preferably made of Nitinol, and may have round, oval, triangular, rectangular, or trapezoidal cross-sectional geometry. The carrier arms may include compound splines or angles, such as to conform to pulmonary vein ostia and surrounding tissue. Each carrier arm may include one or more sensors, such as temperature sensors integral to an ablation element or mounted between two ablation elements, such as to measure tissue temperature and/or blood temperature. In a preferred embodiment, a temperature sensor is mounted to a carrier arm in a location more distal than the most distal ablation element, when the carrier assembly is in a deployed, ready to deliver ablation energy, configuration. Information recorded by the temperature sensor can be used by an energy delivery unit of the present invention as a threshold to avoid overheating of blood or tissue, as well as regulate power to a target temperature. A first carrier arm may have a different property than a second carrier arm, such as a different rigidity, a different number of ablation elements, or a different configuration of sensors such as temperature sensors.

The catheters of the present invention may be configured to be advanced into the heart of a patient over a previously placed guidewire, such as a standard interventional 0.035″ guidewire. The catheter may include an inner lumen for the majority of its length, through which the guidewire is inserted, or the catheter may include a relatively short sidecar near its distal end, where the guidewire inserted through a lumen of the sidecar. The placement over the guidewire allows simplified positioning and re-positioning by an operator. The guidewire placement also provides stability such as to simplify maintaining the position of the catheter during energy delivery, typically 60 seconds.

The catheters of the present invention are configured to be inserted through the lumen of a previously placed transeptal sheath, such as a 9.5 French (Fr) steerable transeptal sheath. The catheter of the present invention preferably include an integral steering mechanism, such as one or more pull wires fixedly attached near a distal portion of the catheter and operably attached to a lever, knob or other control integral to a handle of the catheter. The steering can be used to deflect the carrier assembly and distal end of the catheter into the left and right pulmonary veins of the left atrium. The integral catheter steering can be used in conjunction a steerable transeptal sheath. Multiple pull wires can be fixedly mounted 90° apart at separated locations in a distal portion of the catheter to provide multi-axis, precision controlled steering. The tubular body member of the ablation catheter is constructed with sufficient columnar strength and rigidity to allow an operator to apply significant torque to the proximal end that equivalently translates to the catheters distal portions.

The present invention includes one or more systems that include the ablation catheters of the present invention. The system may further include a guide catheter such as a steerable transeptal sheath that slidingly receives the ablation catheter. The system may further include an energy delivery unit, such as a unit configured to deliver RF and/or other forms of energy to the ablation elements of the catheter. The system may further include a mapping unit that receives information recorded from one or more sensors of the ablation catheter, such as an ablation element of the ablation catheter. The mapping unit provides electrical activity information to an operator of the system. The mapping unit may be integral to the energy delivery unit.

DEFINITIONS

To Facilitate an Understanding of the Invention, a Number of Terms are Defined Below

As used herein, the terms “subject” and “patient” refer to any animal, such as a mammal like livestock, pets, and preferably a human. Specific examples of “subjects” and “patients” include, but are not limited, to individuals requiring medical assistance, and in particular, requiring atrial fibrillation catheter ablation treatment.

As used herein, the terms “catheter ablation” or “ablation procedures” or “ablation therapy,” and like terms, refer to what is generally known as tissue destruction procedures. Ablation is often used in treating several medical conditions, including abnormal heart rhythms. It can be performed both surgically and non-surgically. Non-surgical ablation is typically performed in a special lab called the electrophysiology (EP) laboratory. During this non-surgical procedure a catheter is inserted into the heart using fluoroscopy for visualization, and then an energy delivery apparatus is used to direct energy to the heart muscle. This energy either “disconnects” or “isolates” the pathway of the abnormal rhythm (depending on the type of ablation). It can also be used to disconnect the conductive pathway between the upper chambers (atria) and the lower chambers (ventricles) of the heart. For individuals requiring heart surgery, ablation can be performed during coronary artery bypass or valve surgery.

As used herein, the term “ablation element” refers to an energy delivery element, such as an electrode for delivering electrical energy such as RF energy. Ablation elements can be configured to deliver multiple types of energy, such as ultrasound energy and cryogenic energy, either simultaneously or serially. Electrodes can be constructed of a conductive plate, wire coil, or other means of conducting electrical energy through contacting tissue. Electrodes may comprise a laminate construction, such as at least one conductive layer and at least one insulative layer. RF electrodes preferably are constructed of platinum or a combination of platinum and iridium. In monopolar energy delivery, the energy is conducted from the electrode, through the tissue to a ground pad, such as a conductive pad attached to the back of the patient. The high concentration of energy at the electrode site causes localized tissue ablation. In bipolar energy delivery, the energy is conducted from a first electrode to one or more separate electrodes, relatively local to the first electrode, through the tissue between the associated electrodes. Bipolar energy delivery results in more precise, shallow lesions while monopolar delivery results in deeper lesions. Both monopolar and bipolar delivery provide advantages, and the combination of their use is a preferred embodiment of this application. Energy can also be delivered using pulse width modulated drive signals, well known to those of skill in the art. Energy can also be delivered in a closed loop fashion, such as a system with temperature feedback wherein the temperature modifies the type, frequency and or magnitude of the energy delivered. Ablation elements may have one or more different shapes, such as tubular electrodes mounted around a shaft such as a carrier arm, and other cross-sections such as oval, triangular, rectangular and trapezoidal. Triangular cross sections can be positioned where multiple sides contact tissue for increased energy transfer or multiple sides contact a cooling source such as blood for increased cooling. The ablation elements may include a heat-sinking element, such as a projecting fin or other increased surface area portion. The ablation elements preferably include an integral temperature sensor, such as a thermocouple comprised of copper and constantan wires that are welded inside a mid portion of an RF electrode. In a preferred embodiment, an ablation element can also be used to record and map electrical activity in tissue. In an alternative embodiment, one or more ablation elements may be configured to only map electrical activity, and not be configured to deliver energy.

As used herein, the term “carrier assembly” refers to a flexible carrier, on which one or more ablation elements are disposed. Carrier assemblies include one or more carrier arms. Carrier assemblies are not limited to any particular size, or shape, and can be configured to be in expanded and unexpanded or compact states.

As used herein, the term “carrier arm” refers to a wire-like shaft capable of interfacing with electrodes and a control shaft. A carrier arm is not limited to any size or measurement. Examples include, but are not limited to: stainless steel shafts; Nitinol shafts; titanium shafts; polyurethane shafts; nylon shafts; and steel shafts. Carrier arms can be entirely flexible, or may include flexible and rigid segments.

As used herein, the term “spiral tip” refers to a carrier assembly configured in its fully expanded state into the shape of a helix or spiral. The spiral tip is not limited in the number of spirals it may contain. Examples include, but are not limited to, a wire tip body with one spiral, two spirals, ten spirals, and a half of a spiral. The spirals can lie in a relatively single plane, or in multiple planes. A spiral tip may be configured for energy delivery during an ablation procedure.

As used herein, the term “lesion,” or “ablation lesion,” and like terms, refers to tissue that has received ablation therapy. Examples include, but are not limited to, scars, scabs, dead tissue, burned tissue and tissue with conductive pathways that have been made highly resistive or disconnected.

As used herein the term “umbrella tip” refers to a carrier assembly with a geometric center which lies at a point along the axis of the distal portion of the tubular body member, with one or more bendable or hinged carrier arms extending from the geometric center, in an umbrella configuration. Each carrier arm may include one or more ablation elements. Each carrier arm of an umbrella tip includes a proximal arm segment and a distal arm segment, the distal arm segment more distal than the proximal arm segment when the carrier assembly is in a fully expanded condition. One or more additional carrier arms can be included which include no ablation elements, such as carrier arms used to provide support or cause a particular deflection. An umbrella tip body is not limited to any particular size. An umbrella tip may be configured for energy delivery during an ablation procedure.

As used herein, the term “carrier arm bend point” refers to a joint (e.g., junction, flexion point) located on a carrier arm. The degree of flexion for a carrier arm bend point may range from 0 to 360 degrees. The bend portion can be manufactured such what when the carrier assembly is fully expanded the bend point is positioned in a relatively straight portion, a curved portion, or in a discrete transition from a first direction to a second transition, such as a 45 degree bend transition. The bend portion can include one or more flexing means such as a spring, a reduced diameter segment, or a segment of increased flexibility.

As used herein, the term “energy delivery unit” refers to a device configured to operably attach to an ablation catheter and deliver one or more forms of energy to an ablation element. The energy delivery unit includes a user interface which allows an operator to make one or more settings involved in applying the ablative energy. The energy unit may be further configured to receive temperature information from the ablation catheter. The temperature information can provided to an operator and/or be used to provide closed loop energy delivery. The energy delivery unit may include a remote control device that may be maintained in the sterile field of the patient during the ablation procedure. The energy delivery unit may receive a signal from an operator control integral to the ablation catheter that initiates delivery of the ablation energy.

As used herein, the term “mapping unit” refers to a device configured to operably attach to an ablation catheter and receive one or more mapping signals from an ablation element or other sensor of an ablation catheter.

The present invention provides structures that embody aspects of the ablation catheter. The present invention also provides tissue ablation systems and methods for using such ablation systems. The illustrated and preferred embodiments discuss these structures and techniques in the context of catheter-based cardiac ablation. These structures, systems, and techniques are well suited for use in the field of cardiac ablation.

However, it should be appreciated that the invention is applicable for use in other tissue ablation applications such as tumor ablation procedures. For example, the various aspects of the invention have application in procedures for ablating tissue in the prostrate, brain, gall bladder, uterus, and other regions of the body, preferably regions with an accessible wall or flat tissue surface, using systems that are not necessarily catheter-based.

The multifunctional catheters of the present invention have advantages over previous prior art devices. <figref idref="DRAWINGS">FIGS. 1-17</figref> show various preferred embodiments of the multifunctional catheters of the present invention. The present invention is not limited to these particular configurations.

<figref idref="DRAWINGS">FIG. 1</figref> illustrates a preferred embodiment of an ablation catheter of the present invention with an umbrella tip, wherein a carrier assembly includes multiple carrier arms configured to properly engage a pulmonary vein ostium. Ablation catheter <b>50</b>, and the other catheter devices of this application, are constructed of biocompatible materials suitable for percutaneous advancement through the vasculature of a patient, and for navigation within the patient's heart. Various tubular body members and shafts are constructed of extruded materials such as Pebax, silicones, polyurethanes, polymers, elastomers, flexible plastics and combinations of these. Ablation catheter <b>50</b> includes a distal tip <b>94</b>, which is made of materials to be atraumatic to tissue and which is shown entering the lumen of pulmonary vein <b>15</b> such as to provide a stabilizing and/or anchoring function. Ablation catheter <b>50</b> further includes outer shaft <b>76</b> that preferably has a diameter between 8 and 9 Fr and is constructed to provide sufficient stability and torque through the procedure. Ablation catheter <b>50</b> includes a carrier assembly of the present invention, carrier assembly <b>85</b>, which includes multiple ablation elements <b>92</b> mounted to distal carrier arms <b>88</b>.

The ablation elements <b>92</b> and other components of carrier assembly <b>85</b> are configured to flex to conform to pulmonary vein ostia and other applicable tissues. Outer shaft <b>76</b> can be advanced forward to change the shape of carrier assembly <b>85</b> and cause one or more ablation elements <b>92</b> to contact tissue. Outer shaft <b>76</b> slidingly receives inner shaft <b>78</b>, which is fixedly attached to proximal carrier arms <b>86</b>. Distal carrier arms <b>88</b> are fixedly attached to cap <b>15</b> and the distal end of control shaft <b>84</b>. Proximal carrier arms <b>86</b> are pivotally attached to distal carrier arms <b>88</b>, such that advancement and retraction of control shaft <b>84</b> relative to inner tube <b>78</b> causes the diameter of carrier assembly <b>85</b> to contract and expand respectively, such as to cause the carrier assembly to expand to a 4-5 mm diameter. Inner shaft <b>78</b> further provides columnar strength to allow an operator to advance inner shaft <b>78</b> and cause carrier assembly <b>85</b> to properly contact tissue, such as to conform to non-circular pulmonary vein ostia. Inner shaft <b>78</b> preferably is attached to a pull wire (not shown), near its distal end, which is operably connected to a control on the proximal end of device <b>50</b> allowing an operator to controllably deflect the distal portion of device <b>50</b>.

The distal end of outer shaft <b>76</b> includes a shaft tip <b>82</b>, configured to radially expand when carrier assembly <b>85</b> is retracted. The proximal end of outer shaft <b>76</b> preferably includes a handle, not shown, but including one or more controls, such as knobs or levers, such as to advance and retract inner shaft <b>78</b> and control shaft <b>84</b>. The proximal end of device <b>50</b> includes one or more connectors for connecting to an energy delivery unit and/or a mapping unit. In an alternative embodiment, one or more proximal control arms <b>86</b> are attached to a second control shaft such that the symmetry of the geometry of carrier assembly <b>85</b> can be adjusted to conform to asymmetric pulmonary vein ostia. In another alternative embodiment, device <b>50</b> is configured to be inserted over a previously placed guidewire.

Referring now to <figref idref="DRAWINGS">FIGS. 2</figref><i>a </i>and <b>2</b><i>b</i>, the distal portion of device <b>50</b> of <figref idref="DRAWINGS">FIG. 1</figref> is illustrated. <figref idref="DRAWINGS">FIG. 2</figref><i>a </i>depicts carrier assembly <b>85</b> fully expanded, with inner shaft <b>78</b> fully advanced. <figref idref="DRAWINGS">FIG. 2</figref><i>b </i>depicts inner shaft <b>78</b> partially retracted such that proximal arms <b>85</b> are being captured and radially compressed by shaft tip <b>82</b>, which expands, as shown, to create a smooth transition of carrier assembly <b>85</b> into the inner lumen of outer shaft <b>76</b>.

Referring now <figref idref="DRAWINGS">FIG. 3</figref>, an ablation catheter of the present invention is illustrated comprising two carrier assemblies disposed serially along a single axis, with each carrier assembly in an umbrella tip configuration. Ablation catheter <b>40</b> includes an elongate tube, outer shaft <b>36</b>, preferably constructed of Pebax material and approximately 6-8 Fr in diameter, which slidingly receives first control shaft <b>48</b>. First control shaft <b>48</b> is attached on its distal portion to first carrier assembly <b>45</b>, comprising multiple carrier arms and ablation elements configured to deliver energy. The proximal end of first control shaft <b>48</b>, not shown, is attached to a control on the proximal end of ablation catheter <b>40</b> configured to allow an operator to precisely advance and retract first control shaft <b>48</b>. First control shaft <b>48</b> includes ring <b>52</b> on its distal end that fixedly attaches one end of each distal carrier arm segment <b>44</b> to first control shaft <b>48</b>. Each distal carrier arm segment <b>44</b> is pivotally attached on its opposite end to one end of a proximal carrier arm segment <b>42</b>. The opposite end of each proximal arm segment <b>42</b> is fixedly attached to the distal end of outer shaft <b>36</b> via ring <b>38</b>. Distal carrier arm segments <b>44</b> and proximal arm segments <b>42</b> are constructed of a flexible material, such as Nitinol, and can be resiliently biased in a straight or umbrella tip configuration. Advancement and retraction of first control shaft <b>48</b> changes the diameter of carrier assembly <b>45</b>, including a fully compacted (minimal diameter) radial state when first control shaft <b>48</b> is fully advanced, and a maximum diameter state when first control shaft <b>48</b> is fully retracted.

Fixedly mounted to distal arm segments <b>44</b> are ablation elements, RF electrodes <b>46</b>, configured to deliver energy to tissue to create lesions for disrupting aberrant electrical pathways in the tissue. Electrodes <b>46</b> include fins <b>64</b> configured to reside in a flow of blood during energy delivery and provide sinking of heat into the circulating blood. Electrodes <b>46</b> are configured to deliver monopolar, bipolar or a combination of monopolar and bipolar RF energy as has been described above. Electrodes <b>46</b> preferably include integral temperature sensors, such as a thermocouple welded to an internal portion of the electrode <b>46</b>. Electrode <b>46</b> and any integral temperature or other sensors, are attached to wires, not shown, which travel proximally to the proximal portion of ablation catheter <b>40</b> for attachment to an energy delivery unit, a mapping unit, and/or another electronic device for sending or receiving signals and/or power.

First control shaft <b>48</b> slidingly receives second control shaft <b>57</b>. Second control shaft <b>57</b> is attached on its distal portion to second carrier assembly <b>55</b>, comprising multiple carrier arms and ablation elements configured to map electrical activity. The proximal end of second control shaft <b>48</b>, not shown, is attached to a control on the proximal end of ablation catheter <b>50</b> configured to allow an operator to precisely advance and retract second control shaft <b>57</b>. Second control shaft <b>57</b> includes tip <b>62</b> on its distal end that fixedly attaches one end of each distal carrier arm segment <b>56</b> to second control shaft <b>57</b>. Tip <b>62</b> is preferably constructed of a soft or flexible material such as a soft plastic or elastomer chosen to be atraumatic to tissue, and is preferably radiopaque such as a Pebax material doped with Barium Sulfate. Distal tip <b>62</b> is constructed to help navigation into and stabilization within a pulmonary vein. Distal tip <b>62</b> includes guidewire lumen <b>63</b>, which is in fluid communication with an internal lumen of second control shaft <b>57</b>, the lumen traveling to and exiting a proximal portion of ablation catheter <b>40</b>, such that ablation catheter <b>40</b> can be percutaneously inserted into the vasculature of a patient over a guidewire.

Each distal carrier arm segment <b>56</b> is pivotally attached on its opposite end to one end of a proximal carrier arm segment <b>54</b>. The opposite end of each proximal arm segment <b>54</b> is fixedly attached to the distal end of first control shaft <b>48</b> via ring <b>52</b>. Distal carrier arm segments <b>56</b> and proximal arm segments <b>54</b> are constructed of a flexible material, such as Nitinol, and can be resiliently biased in a straight or umbrella tip configuration. Advancement and retraction of second control shaft <b>57</b> changes the diameter of carrier assembly <b>55</b>, including a fully compacted (minimum diameter) radial state when second control shaft <b>57</b> is fully advanced, and a maximum diameter state when second control shaft <b>57</b> is fully retracted.

Fixedly mounted to distal arm segments <b>44</b> are ablation elements, mapping electrodes <b>58</b>, configured to map electrical activity present in tissue to target areas for creating lesions and/or otherwise assess a patient condition. Electrodes <b>58</b> are constructed of a conductive material such as platinum or a combination of platinum and iridium. Electrodes <b>58</b> preferably include integral temperature sensors, such as a thermocouple welded to an internal portion of the electrode <b>58</b>. Electrode <b>58</b> and any integral temperature or other sensors, are attached to wires, not shown, which travel proximally to the proximal portion of ablation catheter <b>40</b> for attachment to a mapping unit, an energy delivery unit, and/or another electronic device for sending or receiving signals and/or power.

Ablation catheter <b>40</b> of <figref idref="DRAWINGS">FIG. 3</figref> includes on its proximal end, a handle, not shown, but preferably of the type described in reference to <figref idref="DRAWINGS">FIG. 4</figref> and including multiple controls for allowing an operator to: advance and retract first control shaft <b>48</b>; advance and retract second control shaft <b>57</b>; activate energy delivery to one or more of electrodes <b>46</b> or <b>58</b>; operate a user interface of an energy delivery unit or mapping unit (both not shown); or perform another function. The handle includes an exit port through which a guidewire, such as a guidewire that has been placed into a pulmonary vein of the patient, can exit. Carrier assembly <b>55</b> is sized such that it can engage the luminal wall of a pulmonary vein, and carrier assembly <b>45</b> is sized and of sufficient flexibility such that it can engage the ostium of a pulmonary vein, including a non-circular orifice. Outer shaft <b>36</b> is constructed of sufficient material and the handle may be manipulated to apply conforming forces to carrier assembly <b>55</b> and/or carrier assembly <b>45</b>. Both first control shaft <b>48</b> and second control shaft <b>57</b> are configured to transmit sufficient torque to allow an operator to precisely rotationally position carrier assembly <b>45</b> and carrier assembly <b>55</b> respectively.

In an alternative embodiment, the ablation elements <b>46</b> of proximal carrier assembly <b>45</b> may be configured to additionally or alternatively map electrical activity in tissue. In another alternative embodiment, the ablation elements <b>58</b> of distal carrier assembly <b>55</b> may be configured to additionally or alternatively delivery ablation energy such as RF energy. In another alternative embodiment, the carrier arms of carrier assembly <b>45</b> and/or carrier assembly <b>55</b> may include sensors, such as temperature thermocouples, placed within an electrode or mounted to a carrier arm some distance from an electrode, such as midway between two electrodes. Ring <b>38</b> and Ring <b>52</b> are preferably made of a compressible material, such as a metal which can be crimped in a manufacturing process. In an alternative or additional embodiment, adhesives may be used to fixed one or more carrier arms to a shaft. One or more adhesives may be used to attach distal tip <b>62</b>.

Referring Now to <figref idref="DRAWINGS">FIG. 4</figref>, an ablation catheter of the present invention is illustrated including the dual carrier assemblies of the ablation catheter of <figref idref="DRAWINGS">FIG. 3</figref>. Ablation catheter <b>40</b> includes a tubular body member, outer shaft <b>36</b>, which includes on its distal end, proximal carrier assembly <b>45</b> and distal carrier assembly <b>55</b>, as have been described in detail in reference to <figref idref="DRAWINGS">FIG. 3</figref>. The proximal end of outer shaft <b>36</b> is attached to handle <b>66</b>, which includes multiple controls: slide <b>67</b>, slide <b>68</b> and button <b>69</b>. Slide <b>67</b> is operably attached to first control shaft <b>48</b>. Slide <b>68</b> is operably attached to second control shaft <b>57</b>. Movement of slides <b>67</b> and <b>68</b> change the geometries of first carrier assembly <b>45</b> and second carrier assembly <b>55</b> as has been described in detail in reference to <figref idref="DRAWINGS">FIG. 3</figref>. Numerous types of mechanical mechanisms can be incorporated into handle <b>66</b> to operably advance one or more control shafts, such as linear slides, rotating knobs or rotating levers such as knobs connected to cam assemblies, and other mechanisms used to move the shafts forward and back. Button <b>69</b> is used to initiate energy delivery, such as when first carrier assembly <b>45</b> is positioned against a pulmonary vein ostium and ablation catheter <b>40</b> is electrically connected to an energy delivery unit, not shown.

Handle <b>60</b> includes two pigtails, one which terminates in luer <b>74</b> and the other which terminates with electrical connector <b>72</b>. Luer <b>74</b> is in fluid communication with guidewire lumen <b>63</b> exiting tip <b>62</b> such that ablation catheter <b>40</b> can be advanced over-the-wire into the vasculature of the patient. Electrical connector <b>72</b> includes multiple connection points for multiple wires that travel within outer shaft <b>36</b> and connect to ablation elements and one or more sensors such as temperature sensors included in first carrier assembly <b>45</b> and second carrier assembly <b>55</b>. Electrical connector <b>72</b> is configured to electrically connect to one or more of: an energy delivery unit; a mapping unit; an electronic device for receiving and/or transmitting signals and/or power such as signals received from temperature or other physiologic sensors of ablation catheter <b>40</b>; and combinations of these.

Referring now to <figref idref="DRAWINGS">FIG. 5</figref>, an ablation catheter of the present invention is illustrated wherein an ultrasound crystal forwardly directs ultrasonic energy in a circular pattern. Ablation catheter <b>20</b> includes outer shaft <b>22</b>, which slidingly receives control shaft <b>24</b>, both of which have similar construction to the tubular body members and other shafts described throughout this application. Mounted to control shaft <b>24</b> is carrier assembly <b>25</b>, comprising proximal carrier arms <b>26</b> and distal carrier arms <b>28</b>. Proximal carrier arms <b>26</b> and distal carrier arms <b>28</b> are made of a flexible material such as Nitinol wire and may be resiliently biased in the geometry shown or a different geometry such as a radially compact geometry compatible with intravascular insertion. Each proximal carrier arm <b>26</b> is fixedly attached at one end to control shaft <b>24</b>. Each proximal carrier arms <b>26</b> is pivotally attached at its opposite end to an end of distal carrier arms <b>28</b>. The opposite end of each distal carrier arm <b>28</b> is fixedly attached, at a location more distal, to control shaft <b>24</b>, such that a right-angle construction is achieved. A first proximal arm <b>26</b> and attached distal arm <b>28</b> pair is attached 180° from a second proximal arm <b>26</b> and attached distal arm <b>28</b> pair, as shown in <figref idref="DRAWINGS">FIG. 5</figref>. The two pairs are used to contact pulmonary vein ostium <b>30</b>, also as shown. Additional carrier arm pairs may be included, such as a total of four pairs separated by 90°.

Distal to distal carrier arms <b>28</b>, are centering arms <b>32</b>, configured to center control shaft <b>24</b> in the pulmonary vein ostium and/or stabilize the distal portion of ablation catheter <b>20</b> such as during delivery of ablation energy of mapping of electrical activity. Centering arms <b>32</b> are of similar construction to carrier arms <b>26</b> and <b>28</b>, such as a round or flat Nitinol band. Alternatively or in addition to centering arms <b>32</b>, the distal portion of control shaft <b>24</b> may include an inflatable balloon configured to center and/or anchor control shaft <b>24</b>. The centering balloon, not shown, may include one or more mapping and/or energy delivery elements. The centering and/or stabilizing elements of ablation catheter <b>20</b>, such as the centering arms <b>32</b>, an inflatable balloon, or other similarly functioning element, may be integrated into the other ablation devices and catheters described throughout this application. These stabilizing and centering elements are particularly useful when accessing pulmonary vein ostia that are non-circular.

Fixedly mounted to centering arms <b>32</b> are mapping elements <b>34</b>, electrodes configured to record electrical activity found in tissue. Control shaft <b>24</b> includes guidewire lumen <b>31</b>, which exits the distal end of control shaft <b>24</b> and travels proximally and exits a proximal portion of ablation catheter <b>20</b>. In a preferred method, ablation catheter <b>20</b> is advanced over a previously placed guidewire that has its distal end placed into a pulmonary vein of the patient.

Fixedly mounted to external shaft <b>24</b> is ultrasound crystal <b>21</b>, a tubular energy delivery element configured to deliver ultrasonic energy along a cone shaped path, such as along the trajectory of proximal carrier arms <b>26</b> (dashed lines shown on <figref idref="DRAWINGS">FIG. 5</figref>). The vector of energy delivery will cause a relatively circular patterned lesion around the pulmonary vein ostium. In an alternative embodiment, the ultrasound crystal may be configured to provide energy in a sector (less that 360°), and the carrier assembly <b>25</b> would be rotated and repositioned by an operator between ablations to sequentially create a full circumferential lesion.

Advancement and retraction of control shaft <b>24</b> can be used to change the diameter of carrier assembly <b>25</b>, such as retraction wherein the proximal portion of carrier assembly <b>25</b> is captured within the lumen of outer shaft <b>22</b>. Centering arms <b>32</b> are preferably connected to a control shaft, not shown, such that the centering arms can be expanded and contracted. In alternative embodiments with centering and/or stabilizing balloons, or other similar functional elements, the size of the element is configured to be controlled (e.g. expanded and contracted) from the proximal end of the ablation catheter.

Referring now to <figref idref="DRAWINGS">FIG. 6</figref>, an ablation catheter of the present invention is illustrated wherein one or more carrier arms can be rotated along the axis of the distal portion of the outer shaft. Ablation catheter <b>60</b> includes outer shaft <b>96</b>, ring <b>98</b>, ring <b>102</b>, carrier assembly <b>105</b>, ring <b>109</b> and tip <b>106</b>, all of which include similar components, materials, construction and function to the same or like parts used in reference to the ablation catheters described hereabove. Carrier assembly includes multiple proximal carrier arms <b>112</b> which are each at one end fixedly attached to ring <b>102</b>. Proximal carrier arms <b>112</b> are each pivotally attached at their opposite end to one end of distal carrier arms <b>114</b>. The opposite end of each distal carrier arms <b>114</b> is fixedly attached to control shaft <b>101</b> via ring <b>109</b>, such that advancement of control shaft <b>101</b> relative to outer shaft <b>96</b> causes carrier assembly <b>105</b> to change shape. Full advancement of control shaft <b>101</b> causes carrier assembly <b>105</b> to transition to a compact, minimum diameter configuration, and retraction of control shaft <b>101</b> causes carrier assembly <b>105</b> to transition to a maximum diameter configuration, such as for contacting pulmonary vein ostia.

Carrier assembly <b>105</b> further includes a rotatable arm comprising distal arm segment <b>108</b> and proximal arm segment <b>104</b>. One end of distal arm segment <b>108</b> is rotatably attached to control shaft <b>101</b> via ring <b>109</b>. The opposite end of distal arm segment <b>108</b> is pivotally attached to proximal arm segment <b>104</b>. The opposite end of proximal arm segment <b>104</b> is fixedly attached to ring <b>98</b>, which in turn is fixedly attached to a control shaft, not shown but continuing proximally to a control (such as a lever or knob on a handle, both not shown) configured to allow an operator to precisely rotate carrier arm <b>104</b>.

The distal end of control shaft <b>101</b> includes tip <b>106</b>, which is preferably made of flexible material to be atraumatic to tissue. Tip <b>106</b> includes a guidewire lumen <b>107</b> which continues proximally and exits a proximal portion of ablation catheter <b>60</b> such that ablation catheter <b>60</b> can be percutaneously advanced over a previously placed guidewire, such as a guidewire placed into a pulmonary vein as has been described hereabove.

Each distal carrier arms <b>114</b> includes multiple ablation elements <b>116</b> configured to deliver energy to tissue. Distal to the ablation elements <b>116</b> is mapping element <b>118</b> configured to record electrical signals present in tissue. Distal carrier arm <b>108</b> includes multiple ablation elements <b>115</b> configured to deliver energy to tissue. Distal to the ablation elements <b>115</b> is mapping element <b>113</b> configured to record electrical signals present in tissue. Proximal carrier arm <b>104</b> can be rotated and remain concentric with the static carrier arms, such that the ablation elements <b>115</b> on distal arm segment <b>108</b> can be positioned at a specific distance from one or more of the ablation elements <b>116</b> on static distal carrier arms <b>114</b>. The positioning through rotation can be used to achieve lesions of a specific length or other property, especially when bipolar energy is transmitted between ablation element <b>115</b> and one or more ablation elements <b>116</b>. This configuration provides simplified use in creating continuous lesions created one sector at a time. The rotation of proximal arm segment <b>104</b> and distal arm segment <b>114</b> can also be performed to more properly match the contour of a non-circular pulmonary vein ostium.

In an alternative embodiment, ablation catheter <b>60</b> includes multiple rotatable carrier arms, such as carrier arms connected to independent or ganged control shafts such that multiple carrier arms and their integral ablation element can be rotated to modify the carrier assembly geometry.

Referring now to <figref idref="DRAWINGS">FIG. 7</figref>, an ablation catheter is illustrated with a carrier assembly including multiple carrier arms, some of which can be repositioned relative to other carrier arms. Ablation catheter <b>70</b> includes outer shaft <b>130</b>, first control shaft <b>121</b>, second control shaft <b>122</b>, carrier assembly <b>125</b> and ring <b>136</b>, all of which include similar components, materials, construction and function to the same or like parts used in reference to the ablation catheters described hereabove. Carrier assembly <b>125</b> includes multiple carrier arms comprising proximal arm segments <b>124</b>, <b>124</b><i>a </i>and <b>124</b><i>b</i>, each of which are pivotally attached to distal arm segments <b>126</b>, <b>126</b><i>a </i>and <b>126</b><i>b </i>respectively. Proximal arm segments <b>124</b> and distal arm segments <b>126</b>, <b>126</b><i>a </i>and <b>126</b><i>b </i>are fixedly attached on their opposite ends, as has been described hereabove, such that advancement and contraction of control shaft <b>121</b> decreases and increases the diameter of carrier assembly <b>125</b>, respectively.

Ablation catheter <b>70</b> further includes second control shaft <b>122</b> which is hollow at least on its distal portion and surround proximal arm segments <b>124</b><i>a </i>and <b>124</b><i>b </i>such that advancement of control shaft <b>122</b> causes proximal arm segments <b>124</b><i>a </i>and <b>124</b><i>b</i>, each of which includes ablation elements <b>128</b> and mapping element <b>132</b>, to move towards each other, changing the geometry of carrier assembly <b>125</b>, similar to the geometry change causes by rotating a carrier arm as was described in reference to <figref idref="DRAWINGS">FIG. 6</figref>. Both control shaft <b>121</b> and control shaft <b>122</b> are preferably operably connected to a control such as a knob or lever in a handle on the proximal end of ablation catheter <b>70</b>. Repositioning of one or more carrier arms may be performed to increase or decrease the distance between ablation elements, mapping electrodes or other arm-mounted sensors or transducers. Repositioning of the arms may also be performed to better conform to various pulmonary vein anatomies, such as pulmonary veins with non-circular ostia.

Ablation device <b>70</b> of <figref idref="DRAWINGS">FIG. 7</figref> further includes an elongate floppy tip <b>134</b>, preferably of a guidewire-like construction, to assist in entering an orifice such as a pulmonary vein lumen, or in maintaining stability during a mapping or ablating procedure. In an alternative embodiment, ablation device <b>70</b> includes a guidewire lumen from a proximal portion of the device to a distal portion of the device.

Referring now to <figref idref="DRAWINGS">FIG. 8</figref><i>a</i>, an ablation catheter of the present invention is illustrated in which multiple carrier arms are maintained in fixed positions by a ring, such as an advancable ring. Ablation catheter <b>90</b> includes outer shaft <b>138</b>, control shaft <b>141</b>, carrier assembly <b>145</b> and tip <b>154</b>, all of which include similar components, materials, construction and function to the same or like parts used in reference to the ablation catheters described hereabove. Carrier assembly <b>145</b> includes proximal arm segments <b>144</b> which are pivotally attached to distal arm segments <b>146</b>. Each distal arm segment <b>146</b> includes multiple ablation electrodes <b>147</b> and a mapping sensor <b>148</b> distal to the ablation electrodes <b>147</b>. Carrier assembly <b>145</b> further includes multiple carrier arms <b>156</b>, which may be void of electrodes as shown, or may include one or more mapping or ablating electrodes, or other sensor or transducer.

Referring also to <figref idref="DRAWINGS">FIG. 8</figref><i>c</i>, each proximal carrier arm segment is circumferentially positioned in a groove <b>246</b> of ring <b>142</b>. Carrier arms <b>156</b> are similarly positioned in a groove <b>256</b> of ring <b>142</b>. Ring <b>142</b> is preferably attached to a control shaft, not shown, such that advancement of that control shaft changes the geometry of carrier assembly <b>145</b> accordingly. Retraction of control shaft <b>141</b> changes the diameter of carrier assembly <b>145</b> as has been described in detail hereabove. <figref idref="DRAWINGS">FIG. 8</figref><i>b </i>illustrates an end view of the ablation catheter <b>90</b> of <figref idref="DRAWINGS">FIG. 8</figref><i>a</i>, showing the rotational orientation of the distal arm segments <b>146</b> and carrier arms <b>156</b>. Carrier arms <b>156</b> are positioned orthogonal to two sets of three distal carrier arms <b>146</b> such as to provide positioning and radial support to distal carrier arms <b>146</b>. Various configurations of carrier arm geometries can be provided for handling of various pulmonary vein tissue contours. Ring <b>142</b> may maintain the ablation elements <b>147</b> and/or the mapping elements <b>148</b> in close proximity.

In an alternative embodiment, ring <b>142</b> is not advancable (not connected to a control shaft), but included with grooves <b>256</b> and grooves <b>246</b> to maintain the rotational orientation of the distal carrier arms <b>146</b> and the carrier arms <b>156</b> such as when force is applied to outer shaft <b>138</b>, such as via a handle, the force translated to carrier assembly <b>145</b>.

Referring now to <figref idref="DRAWINGS">FIG. 9</figref>, an ablation catheter of the present invention is illustrated in which an advancable spline can be radially expanded to improve or otherwise alter the structure and rigidity of a carrier assembly. Ablation catheter <b>90</b><i>b </i>includes outer shaft <b>138</b>, control shaft <b>141</b>, carrier assembly <b>95</b> and tip <b>154</b>, all of which include similar components, materials, construction and function to the same or like parts used in reference to the ablation catheters described hereabove. Carrier assembly <b>95</b> includes multiple carrier arms <b>156</b> in an umbrella tip configuration, one or more including ablation elements, other sensors or transducers, all not shown. As control shaft <b>141</b> is advanced and retracted (e.g. via a control on a proximal handle, both not shown), carrier assembly <b>95</b> contracts and expands respectively, as has been described hereabove. Control shaft <b>141</b> slidingly receives an advancable spline <b>164</b>, whose distal end resides in recess <b>162</b> of control shaft <b>141</b>. Advancement of spline <b>164</b> causes its distal end to extend radially out from control shaft <b>141</b> as is shown in <figref idref="DRAWINGS">FIG. 9</figref><i>a </i>(partially extended) and <figref idref="DRAWINGS">FIG. 9</figref><i>b </i>(fully extended). In a preferred embodiment, spline <b>164</b> can be advanced to the maximum diameter of carrier arms <b>156</b>. In an alternative embodiment, spline <b>164</b> can be advanced to a diameter greater than the maximum diameter of carrier arms <b>156</b>. Spline <b>164</b> is advance to modify the performance characteristics of carrier assembly <b>95</b>, such as to modify the supporting forces applied to tissue. In an alternative embodiment, spline <b>164</b> includes one or more ablation elements <b>165</b> (e.g. RF electrodes) or other sensors or transducers.

Referring now to <figref idref="DRAWINGS">FIGS. 10 and 11</figref>, an ablation catheter of the present invention is illustrated in which the carrier assembly comprises an inflatable balloon with multiple ablation elements mounted on or embedded in its external surface. Ablation catheter <b>100</b> includes carrier assembly <b>175</b> comprising balloon <b>174</b> and electrodes <b>172</b>, such as RF ablation or electrical signal mapping electrodes. Ablation catheter <b>100</b> further includes an elongate tubular body, outer shaft <b>166</b>, which includes an inflation lumen <b>176</b> from its proximal portion to the inner cavity of balloon <b>174</b>. Balloon <b>174</b> is sealed and fixedly attached to the distal portion of outer shaft <b>166</b>. Passage of fluid such as air or saline through the inflation lumen of outer shaft <b>166</b> causes balloon <b>174</b> to inflate and remain in an expanded state as long as the fluid pressure is maintained. Balloon <b>174</b> may be a compliant or non-compliant balloon, and while shown as a disk or donut shape, may have profiles specific to mimic pulmonary vein ostia and the tissue extending therefrom.

Extending from the distal end of and coaxial to external shaft <b>166</b> is centering post <b>168</b> which traverses from the proximal end to the distal end of balloon <b>174</b>, and includes a projection configured to engage a pulmonary vein lumen. In a preferred embodiment, a guidewire lumen is included from the distal end to a proximal portion of ablation catheter <b>100</b> such that ablation catheter may be advanced over a guidewire such as a guidewire that has previously been placed into a pulmonary vein ostium or other applicable orifice. Mapping and/or ablating procedures can be accomplished by an operator applying a force to balloon <b>174</b> via shaft <b>166</b>, and transmitting ablation energy to electrodes <b>172</b> and/or recording electrical activity from electrodes <b>172</b>.

Referring now to <figref idref="DRAWINGS">FIG. 12</figref><i>a</i>, ablation catheter of the present invention is illustrated in which the carrier assembly includes a single carrier arm that can be positioned into an adjustable, partial circumferential (less than 360°) loop for ablating and/or mapping tissue. Ablation device <b>180</b> includes an elongate tubular body member, outer shaft <b>182</b>, with sufficient column and torsion strength to support standard interventional procedures such as those which access the vasculature from a femoral vein or artery and access the patient's heart. Outer shaft <b>182</b> is constructed of biocompatible materials such as Pebax, and preferably includes an inner braid, such as a stainless steel 304 braid. The proximal portion of outer shaft <b>182</b> is preferably made of Pebax 7233D and the distal portion of outer shaft <b>182</b> is preferably made of Pebax 55/3533D. Outer shaft <b>182</b> is fixedly attached to handle <b>195</b> via strain relief <b>181</b>.

Exiting the distal end of outer shaft <b>182</b> are control shaft <b>184</b> and carrier assembly <b>185</b>, which comprises a single carrier arm <b>186</b>. At least one of control shaft <b>184</b> and carrier arm <b>186</b> can be advanced and/or retracted by manipulating a control on handle <b>195</b>, such as rotating knob <b>193</b>. In a preferred embodiment, the proximal end of carrier arm <b>186</b> is fixedly attached to a distal portion of outer shaft <b>182</b>, such as via a crimp and/or adhesives, and control shaft <b>184</b> is slidingly received by outer shaft <b>182</b> and operably attached to rotating knob <b>193</b>. Carrier arm <b>185</b>, preferably made of an elastic material such as Nitinol covered with a sleeve made of Pebax, includes one or more electrodes <b>188</b> along its length. The electrodes <b>188</b> may include heat-sinking fins as shown. The electrodes <b>188</b> are preferably made of platinum, and are typically 3 mm long and separated by 1 to 4 mm, with symmetric or asymmetric spacing. Four electrodes <b>188</b> are depicted in <figref idref="DRAWINGS">FIGS. 12</figref><i>a </i>through <b>12</b><i>c</i>. Four (4) to sixteen (16) electrodes <b>188</b> are preferred, typically eight (8) to ten (10). The presence of multiple, typically uniformly distributed electrodes enables the operator to rapidly identify problematic target areas (undesired electrical activity) and create lesions (ablate) rapidly. The multi-electrode geometry of carrier assembly <b>185</b>, precision loop control, and ease of positioning (including over-the-wire positioning and anchoring), enables simplified, customized diagnosis and treatment of heart rhythm disorders such as atrial fibrillation.

Electrodes <b>188</b> may be for delivering of ablation energy, for mapping of electrical activity, and/or for performing other functions such as pacing of the heart. Alternatively or additionally, carrier arm <b>185</b> may include different types of sensors and/or transducers, such as sensors or transducers that can be applied to the ostium of a vessel to perform a diagnostic and/or therapeutic function. The distal end of carrier arm <b>185</b> is fixedly attached to the distal end of control shaft <b>184</b>, the connection point encased by tip <b>192</b>. Tip <b>192</b> is of materials and construction to be atraumatic, such as a Pebax tip, which has been doped with Barium Sulfate in order to be radiopaque. Tip <b>192</b> includes guidewire lumen <b>191</b>, a through hole which travels proximally, through control shaft <b>184</b>, and exits handle <b>195</b> at guidewire exit hole <b>199</b>, configured such that ablation device <b>180</b> can be percutaneously advanced over a guidewire which has had its distal end inserted into a pulmonary vein of the patient.

Handle <b>195</b>, preferably made of a plastic such as a polycarbonate, includes lever <b>196</b> which is operably attached to one or more pull wires, not shown, that travel within a lumen of outer shaft <b>182</b> and attach near the distal end of shaft <b>182</b>. Multiple pull wires may be included, such as two pull wires which are attached at a 90° radial separation from each other near the distal end of shaft <b>182</b>. The two pull wires may be attached at the same longitudinal position along the axis of shaft <b>182</b>, or may be offset. Manipulation of lever <b>196</b> causes the distal portion of ablation catheter <b>180</b> to deflect in one or more planes such that a clinician can manipulate tip <b>192</b> into a pulmonary vein or other orifice such as the coronary sinus or other vessel.

Handle <b>195</b> also includes plug <b>198</b> which is configured to electrically connect to one or more separate devices, such as an energy delivery unit configured to deliver ablation energy to electrodes <b>188</b> and/or to receive temperature signals from one or more temperature sensors such as a thermocouple integral to an electrode <b>188</b>; a mapping unit configured to receive electrical signals from one or more electrodes <b>188</b>; a pacing unit configured to deliver electrical energy to electrodes <b>188</b> in order to pace the heart of a patient; or another device such as a device which receives and/or transmits signals to one or more functional elements of carrier assembly <b>185</b>. Wires, not shown, attach to plug <b>198</b> and travel through handle <b>195</b>, through outer shaft <b>182</b> and attach to electrodes <b>188</b> and any other sensors or transducers integral to electrodes <b>188</b> or attached to carrier arm <b>186</b>. The wires may be located on the external surface of carrier arm <b>186</b>, or travel within a lumen of carrier arm <b>186</b>, exiting through a side hole to attach to electrodes <b>188</b>.

Referring additionally to <figref idref="DRAWINGS">FIG. 12</figref><i>b</i>, carrier assembly <b>185</b> is shown in a linear configuration such that ablation device <b>180</b> can be intraluminally advanced through the vasculature of the patient. Carrier assembly <b>185</b> is placed in this linear configuration by advancing control shaft <b>184</b> such as via rotating knob <b>193</b> of handle <b>195</b>. Referring now to <figref idref="DRAWINGS">FIG. 12</figref><i>c</i>, control shaft <b>184</b> is being retracted, and carrier assembly <b>185</b> is transitioning to a partial circumferential (less than 360°) loop. Advancement and retraction of control shaft <b>184</b> adjust the geometry of the loop, wherein full advancement causes a near-linear configuration and retraction causes the diameter of carrier assembly <b>185</b> to increase. Preferred maximum diameters of carrier assembly <b>185</b> are typically 15-32 mm to accommodate the varied anatomical contours neighboring pulmonary vein ostia (including non-circular ostia). The simplified loop-modifying controls of the present invention allow for rapid positioning by an operator. In a preferred embodiment, carrier arm <b>186</b> is resiliently biased (such as with the heat treating of a Nitinol component) in a helical configuration. In an alternative embodiment, carrier arm <b>186</b> is resiliently biased in a near-linear configuration. In the configuration where carrier arm <b>186</b> includes a wire surrounded by a sleeve, a resilient bias can be provided by the wire or the sleeve.

In another alternative embodiment, the proximal end of carrier arm <b>186</b> exits outer shaft <b>182</b> at a location approximate 90° radially offset from the location that carrier arm <b>186</b> is attached to the distal end of control shaft <b>184</b>, such offset attachment providing a bias for forming the loop during retraction of control shaft <b>184</b>.

Carrier assembly <b>185</b> may include a loop of 360° or more. In another alternative embodiment, outer shaft <b>182</b> may include a mechanical key to maintain the rotational orientation of control shaft <b>184</b> and/or carrier arm <b>186</b>. Control shaft <b>184</b> may include an attachment ring near its distal end such as for attachment to the proximal end of carrier arm <b>186</b>. In another preferred embodiment, carrier assembly <b>185</b> includes at least one temperature sensor more distal than the most distal ablation element delivering ablation energy, such that the maximum distal (e.g. into the pulmonary vein lumen) temperature is always monitored (e.g. to prevent creation of a pulmonary vein stenosis). In the configuration of <figref idref="DRAWINGS">FIGS. 12</figref><i>a </i>through <b>12</b><i>c</i>, both control shaft <b>184</b> and carrier arm <b>186</b> exit the distal end of outer shaft <b>182</b>. In an alternative embodiment, either or both control shaft <b>184</b> or carrier arm <b>186</b> exit a side hole of outer shaft <b>182</b> (not shown but near the distal end of outer shaft <b>182</b>). In another alternative embodiment, control shaft <b>184</b> may be rotated, such as via a control on handle <b>195</b>, to further change the geometry of carrier assembly <b>185</b>.

Referring now to <figref idref="DRAWINGS">FIGS. 13</figref>, <b>13</b><i>a </i>and <b>13</b><i>b</i>, the ablation catheter of <figref idref="DRAWINGS">FIG. 12</figref><i>a </i>is illustrated. In <figref idref="DRAWINGS">FIG. 13</figref>, ablation catheter <b>180</b> is shown with carrier assembly <b>185</b> in linear configuration such as for advancing ablation catheter <b>180</b> over guidewire <b>12</b>, such as an intraluminal advancement over a guidewire which has been inserted into a femoral vein, and travels to the heart, through the septum separating the right atrium and left atrium (e.g. through a transeptal sheath), and into a pulmonary vein such as the left superior pulmonary vein. Carrier assembly <b>185</b> is placed in this linear, maximally compact configuration by advancing control shaft <b>184</b>, such as by manipulating a control on a handle of device <b>180</b> as has been described hereabove. Carrier arm <b>186</b> includes electrodes <b>188</b>. Carrier arm <b>186</b> has a proximal end fixedly attached to outer shaft <b>182</b> via crimp ring <b>194</b>. Carrier arm <b>186</b> distal end is fixedly attached to control shaft <b>184</b> at a radial location that is 90° offset from its proximal end attachment (as shown in <figref idref="DRAWINGS">FIG. 13</figref>), such that carrier assembly <b>185</b> radially expands as shown in <figref idref="DRAWINGS">FIGS. 13</figref><i>a </i>and <b>13</b><i>b </i>as control shaft <b>184</b> is retracted. The distal end of control shaft <b>184</b> is covered with atraumatic tip <b>192</b>, which includes an exit hole in communication with an internal guidewire lumen, not shown but through which guidewire <b>12</b> passes.

Referring now to <figref idref="DRAWINGS">FIG. 14</figref>, a preferred construction of the ablation catheter of <figref idref="DRAWINGS">FIG. 12</figref><i>a </i>is illustrated. Ablation catheter <b>180</b> includes carrier assembly <b>185</b>, which comprises a single carrier arm <b>186</b> whose geometry is adjusted by advancing and retracting control shaft <b>184</b>, as has been described in detail hereabove. Carrier arm <b>186</b> includes wire shaft <b>202</b>, preferably Nitinol or other shaped memory alloy or polymer, surrounded by outer sleeve <b>203</b>, preferably Pebax or other biocompatible, soft material. Sleeve <b>203</b> can perform one or more functions, including but not limited to: capturing one or more wires between wire <b>202</b> and sleeve <b>203</b>; acting as an insulator; providing an atraumatic boundary (e.g. covering any sharp edges of wire <b>202</b>); and combinations thereof. Wire shaft <b>202</b> preferably is resiliently biased in the loop geometry depicted. The proximal end of carrier arm <b>186</b> is fixedly attached to outer shaft <b>182</b> via ring <b>194</b>. Alternatively or additionally, adhesives such as cyanoacrylate may be used for fixation. In an alternative embodiment, ring <b>194</b> also functions as an electrode, such as a mapping and/or ablation electrode.

At its distal end, carrier arm <b>186</b> is fixedly attached to cap <b>192</b> and the distal end of control shaft <b>184</b>. Cap <b>192</b> is of soft construction to be atraumatic to tissue, and is preferably made of Pebax which has been doped with Barium Sulfate to be radiopaque. A guidewire lumen <b>201</b> exits cap <b>192</b> after having passed within control shaft <b>184</b>. Guidewire lumen <b>201</b> is surrounded by a braided tube preferably made of Nylon and braided with stainless steel wire. The guidewire lumen <b>201</b> travels proximally to an exit port on a handle, not shown but described in detail hereabove.

Electrodes <b>188</b> are fixedly mounted to carrier arm <b>186</b>, such as with cyanoacrylate (or other adhesive) beads <b>204</b>. Each electrode <b>188</b> preferably includes a thermocouple, not shown but preferably a copper-constantan wire junction welded to an internal surface of electrode <b>188</b>. Each electrode, and any included thermocouple, is attached to one or more wires (attachment not shown), which are grouped with other wires to form wire bundle <b>210</b>, which travels proximally and is attached to an electrical port on the proximal end of ablation catheter <b>180</b>. Carrier arm <b>184</b> may include other sensors or transducers, some of which may also be attached to wires included in wire bundle <b>210</b>, these sensors or transducers placed against tissue such as pulmonary vein ostial tissue to perform a diagnostic or therapeutic procedure in a patient.

<figref idref="DRAWINGS">FIG. 14</figref> further illustrates a preferred construction of the distal portion of outer shaft <b>182</b>. Immediately proximal to ring <b>194</b> is distal segment <b>205</b>, preferably made of Pebax 5533 or 6333. Immediately proximal to distal segment <b>205</b> is hinge segment <b>206</b>, and proximal to hinge segment <b>206</b> is wall <b>212</b>. Hinge segment <b>206</b> is preferably made of a softer material than distal segment <b>205</b> and wall <b>212</b>, such as Pebax 3533. Mounted within hinge segment <b>206</b> is second anchor ring <b>211</b>, a metal (e.g. stainless steel) ring that is fixedly attached to two (2) pull wires <b>209</b>. Pull wires <b>209</b> extend proximally and are attached to a knob, lever or other control integral to a handle, all not shown but operably configured to deflect the distal end of ablation catheter <b>180</b> in multiple planes. Wall <b>212</b> surrounds braid <b>207</b> and braid <b>207</b> surrounds liner <b>208</b>. Braid <b>207</b>, a standard catheter braid to provide column and torsion support, is preferably made of stainless steel such as 304 stainless steel. Liner <b>208</b> is preferably made of Teflon or another lubricious material that allows one or more shafts, such as control shaft <b>184</b> and pull wires <b>209</b>, to be slidingly received within a lumen of shaft <b>182</b> without significant resistance.

Referring now to <figref idref="DRAWINGS">FIGS. 15</figref><i>a </i>through <b>15</b><i>d</i>, the ablation catheter of <figref idref="DRAWINGS">FIG. 12</figref><i>a </i>is illustrated. Ablation catheter <b>180</b> includes outer shaft <b>182</b>, control shaft <b>184</b>, ring <b>194</b>, carrier assembly <b>185</b> and tip <b>192</b>, all of which include similar components, materials, construction and function to the same or like parts used in reference to the ablation catheters described hereabove. <figref idref="DRAWINGS">FIG. 15</figref><i>a </i>illustrates the proximal portion, including handle, preferably made of a plastic such as polycarbonate. Handle <b>195</b> includes lever <b>196</b> and slide <b>197</b>, controls used by an operator to adjust the carrier assembly, deflect the distal portion of catheter <b>180</b> and/or perform other functions. Handle <b>195</b> is fixedly attached to shaft <b>182</b>. Extending from handle <b>195</b> is pigtail plus <b>198</b>, an electrical connector that attaches signal and power wires to one or more components of ablation catheter <b>180</b> such as ablation electrodes, mapping electrodes and thermocouples.

Referring now to <figref idref="DRAWINGS">FIG. 15</figref><i>b</i>, the distal end of catheter <b>180</b> is illustrated including the distal end of outer shaft <b>182</b>. <figref idref="DRAWINGS">FIG. 15</figref><i>b </i>illustrates carrier assembly <b>185</b> in its compacted, linear configuration applicable for over-the-wire intraluminal advancement of ablation catheter <b>180</b>, such as to reach the left superior pulmonary vein as depicted in <figref idref="DRAWINGS">FIG. 15</figref><i>d</i>. Referring back to <figref idref="DRAWINGS">FIG. 15</figref><i>b</i>, control shaft <b>184</b> has been fully advanced such that carrier arm <b>186</b> is pulled tight against control shaft <b>184</b>. Control shaft <b>184</b> includes on its distal end tip <b>192</b>. Within tip <b>192</b> is guidewire lumen <b>191</b> through which a standard interventional guidewire, such as a 0.035″ guidewire, can be inserted. Carrier arm <b>185</b> is configured, as has been described in detail hereabove, such that upon retraction of control shaft <b>184</b>, carrier arm <b>186</b> extends laterally into the loop configuration illustrated in <figref idref="DRAWINGS">FIG. 15</figref><i>c. </i>

Referring additionally to <figref idref="DRAWINGS">FIG. 15</figref><i>d</i>, the treatment to be accomplished with the devices and method described in this application is illustrated. <figref idref="DRAWINGS">FIG. 15</figref><i>d </i>shows a cutaway view of the human heart <b>10</b>, showing the major structures of the heart including the left and right atria, and the pulmonary veins <b>15</b>. The atrial septum separates the left and right atria. The fossa ovalis is a small depression in the atrial septum that may be used as an access pathway to the left atrium from the right atrium, such as with a transeptal puncture device and transeptal sheath. The fossa ovalis can be punctured, and easily reseals and heals after procedure completion. In a patient suffering from atrial fibrillation, aberrant electrically conducive tissue may be found in the atrial walls, as well as in the pulmonary veins <b>15</b>. Ablation of these areas, referred to arrhythmogenic foci (also referred to as drivers or rotors), is an effective treatment for atrial fibrillation. The catheters of the present invention provide means of creating lesions, including lesions to surround the pulmonary vein ostia, and are easily deployed to identify and ablate the driver and rotor tissue.

To accomplish this, catheter <b>180</b> is inserted into the right atrium, preferably through the inferior vena cava, as shown in the illustration, or through the superior vena cava. Catheter <b>180</b> is sized for this advancement through the patient's vasculature, such as where the inserted (shaft) diameter is approximately 9 Fr, the shaft length is approximately 115 cm and the overall length is typically 158 cm. Catheter <b>180</b> has been passed through transeptal sheath <b>11</b>, which may or may not be a deflectable sheath since catheter <b>180</b> preferably includes a deflectable distal portion. When passing into the left atrium, transeptal sheath <b>11</b> passes through or penetrates the fossa ovalis, such as over guidewire <b>12</b> which may have been placed by a transeptal puncture device. Catheter <b>180</b> is inserted over guidewire <b>12</b> and through transeptal sheath <b>11</b> such that its distal end enters right superior pulmonary vein <b>15</b>'s lumen. The distal portion of shaft <b>182</b> has been deflected such that the distal end of shaft <b>182</b> is directed toward the lumen of pulmonary vein <b>15</b><i>a</i>. Catheter <b>180</b> carries a structure carrying multiple ablation elements such as RF electrodes, carrier assembly <b>185</b>, into the left atrium. Carrier assembly <b>185</b> has been transitioned to expand to a maximal diameter by retracting control shaft <b>184</b>, such that multiple ablation elements (ablation and/or mapping elements), electrodes <b>188</b>, are in contact with the pulmonary vein ostial tissue. Carrier assembly <b>185</b> is adapted to be deformable such that pressing carrier assembly into pulmonary vein <b>15</b> ostium will cause one or more, and preferably all of electrodes <b>188</b> to make contact with tissue to be analyzed and/or ablated. Each of the electrodes <b>188</b> is attached via connecting wires and one or more connectors, such as plug <b>198</b>, to an energy delivery apparatus, not shown but preferably an RF energy delivery unit which is also attached to a patch electrode, also not shown but preferably a conductive pad attached to the back of the patient.

The energy delivery unit is configured to delivery RF energy in monopolar, bipolar or combination monopolar-bipolar energy delivery modes, simultaneously or sequentially, with or without “off” or no energy delivered time durations. In a preferred embodiment, the energy delivery unit <b>200</b> is configured to also provide electrical mapping of the tissue that is contacted by one or more electrodes integral to carrier assembly <b>185</b>. Alternatively, a separate mapping unit may be used, preferably attached to catheter <b>180</b> simultaneous with attachment to the energy delivery unit. Electrodes <b>188</b> can also be configured to be mapping electrodes and/or additional electrodes can be integral to carrier assembly <b>185</b> to provide a mapping function. Carrier assembly <b>185</b> is configured to be engaged over a pulmonary vein ostium surface to map and/or ablate tissue on the surface. Energy is delivered after a proper location of the electrodes <b>188</b> is confirmed with a mapping procedure. If conditions are determined to be inadequate, an operator may adjust the shape of carrier assembly <b>185</b> (e.g. through advancement or retraction of control shaft <b>184</b>) and/or the operator may reposition carrier assembly <b>185</b> against tissue through various manipulations at the proximal end of the ablation catheter <b>180</b>. After an ablation step is completed, ablation catheter <b>180</b> is repositioned, with or without changing the geometry of carrier assembly <b>185</b>, and a similar mapping and ablation step is performed. For each pulmonary vein ostium, this repositioning will typically occur two to three times creating semi-circular lesions that preferably overlap. The steerability of the distal portion of shaft <b>182</b>, via a control on handle <b>195</b>, is an important function in this repositioning process. In a typical procedure, the clinician will perform ablations in the left superior pulmonary vein first, followed by the right superior, left inferior and then the right inferior pulmonary veins.

In a preferred embodiment, the energy delivery unit is configured to delivery both RF energy and ultrasound energy to the identical or different electrodes <b>188</b>. In another preferred embodiment, the energy delivery unit is configured to accept a signal from one or more sensors integral to ablation catheter <b>180</b>, not shown, such that the energy delivered can be modified via an algorithm which processes the information received from the one or more sensors.

In an alternative embodiment, a guidewire is inserted through a sidecar present at the distal portion of shaft <b>182</b>, avoiding the need for threading the entire the device over the guidewire. In another alternative embodiment, carrier arm <b>186</b> is attached to a second control shaft, also slidingly received by outer shaft <b>182</b> and connected to a control on handle <b>195</b>, such that the carrier assembly <b>185</b> geometry can be adjusted by advancing and retracting either the second control shaft or control shaft <b>184</b>. This dual control shaft design also allows carrier assembly to be completely retracted within the distal end of control shaft <b>182</b>, as is described in reference to <figref idref="DRAWINGS">FIG. 17</figref> herebelow.

Referring now to <figref idref="DRAWINGS">FIG. 16</figref>, an ablation catheter of the present invention is illustrated comprising a first deployable carrier assembly including multiple ablation electrodes and a more distal second deployable carrier assembly including multiple mapping electrodes. Ablation catheter <b>400</b> includes outer shaft <b>410</b>, first control shaft <b>411</b>, second control shaft <b>412</b>, first carrier assembly <b>430</b><i>a</i>, second carrier assembly <b>430</b><i>b </i>and tip <b>415</b>, all of which include similar components, materials, construction and function to the same or like parts used in reference to the ablation catheters described hereabove. Outer shaft <b>410</b>, preferably a braided construction including braid <b>413</b>, slidingly receives first control shaft <b>410</b>, which in turn slidingly receives second control shaft <b>411</b>. Outer shaft <b>410</b> is fixedly attached to handle <b>420</b> via strain relief <b>426</b>. An atraumatic tip <b>415</b> is fixedly attached to the distal end of second control shaft <b>412</b>. A guidewire lumen <b>416</b> exits tip <b>415</b> and travels proximally, through second control shaft <b>412</b>, first control shaft <b>411</b> and outer shaft <b>410</b> to handle <b>420</b> where it exits via guidewire entry <b>424</b>, such that ablation catheter <b>400</b> can be percutaneously introduced into a patient over a previously placed guidewire.

First carrier assembly <b>430</b><i>a </i>comprises a single carrier arm, first carrier arm <b>433</b>, which is fixedly attached on its distal end to the distal end of first control shaft <b>411</b> and on its proximal end to the distal end of outer shaft <b>410</b>. First control shaft <b>411</b> is operably connected on its proximal end to first advancable knob <b>421</b>, such that advancement and retraction of knob <b>421</b> causes advancement and retraction of first control shaft <b>411</b>. Advancement and retraction of first control shaft <b>411</b> causes first carrier assembly <b>430</b><i>a </i>to contract and expand, respectively, as has been described hereabove. Full advancement of first control shaft <b>411</b> causes first carrier assembly <b>430</b><i>a </i>to have a minimum diameter (fully constrained near-linear configuration) and full retraction of control shaft <b>411</b> causes first carrier assembly <b>430</b><i>a </i>to have a maximum diameter. First carrier assembly <b>430</b><i>a </i>includes electrodes <b>431</b>, and each electrode <b>431</b> is preferably at least configured to deliver ablation energy to tissue.

Second carrier assembly <b>430</b><i>b </i>comprises a single carrier arm, second carrier arm <b>434</b>, which is fixedly attached on its distal end to the distal end of second control shaft <b>412</b> and on its proximal end to the distal end of first control shaft <b>411</b>. Second control shaft <b>412</b> is operably connected on its proximal end to second advancable knob <b>422</b>, such that advancement and retraction of knob <b>422</b> causes advancement and retraction of second control shaft <b>412</b>. Advancement and retraction of first control shaft <b>411</b> (via advancement and retraction of knob <b>421</b>) causes second carrier assembly <b>430</b><i>b </i>to expand and contract, respectively. Also, advancement and retraction of second control shaft <b>412</b> (via advancement and retraction of knob <b>422</b>) causes second carrier assembly <b>430</b><i>b </i>to contract and expand, respectively, as has been described hereabove. Advancement and retraction of first control shaft <b>411</b> and second control shaft <b>412</b>, in combination or independently, changes the geometry of second carrier assembly <b>430</b><i>b </i>accordingly. For intraluminal advancement of ablation catheter <b>400</b>, both first carrier assembly <b>430</b><i>a </i>and second carrier assembly <b>430</b><i>b </i>are placed in a minimal diameter configuration. Second carrier assembly <b>430</b><i>b </i>includes electrodes <b>432</b>, and each electrode <b>432</b> is preferably at least configured to record electrical activity present in tissue. Electrodes <b>431</b> and electrodes <b>432</b> preferably include an integral temperature sensor, such as a thermocouple constructed of a copper-constantan bimetallic assembly. Electrodes <b>431</b> may be further configured to record electrical signals in tissue and electrodes <b>432</b> may be further configured to deliver ablation energy to tissue.

Handle <b>420</b> also includes lever <b>423</b>, which is operably attached to one or more pull wires which extend distally within a lumen, such as a Teflon lined lumen, within outer shaft <b>410</b>. The one or more pull wires are fixedly attached to a distal portion of outer shaft <b>410</b> causing operator controlled deflection of the distal portion of ablation catheter <b>400</b> in one or more planes. Handle <b>420</b> further includes electrical plug <b>425</b> which is electrically connected to one or more electrical wires or other conduits, all of which travel distally, along outer shaft <b>410</b> to various locations such as electrodes <b>431</b> or electrodes <b>432</b>, or another sensor or transducer not shown. Plug <b>425</b> is configured to attach to an energy delivery unit such as an RF energy delivery unit, a mapping unit or another device configured to transmit or receive electrical signals or power.

<figref idref="DRAWINGS">FIG. 16</figref><i>a </i>illustrates an end view of the ablation catheter of <figref idref="DRAWINGS">FIG. 16</figref>. First carrier assembly <b>430</b><i>a </i>and second carrier assembly <b>430</b><i>b </i>are both in their maximum diameter configurations. <figref idref="DRAWINGS">FIG. 16</figref><i>b </i>illustrates a side view of the ablation catheter of <figref idref="DRAWINGS">FIGS. 16 and 16</figref><i>a </i>inserted into a vessel, such as a pulmonary vein <b>15</b>, through its ostium. Second carrier assembly <b>430</b><i>b </i>is partially or fully expanded and in contact with the luminal wall of vein <b>15</b>. First carrier assembly <b>430</b><i>a </i>is partially or fully expanded and engaging the ostium of vein <b>15</b>.

Referring now to <figref idref="DRAWINGS">FIGS. 17</figref>, <b>17</b><i>a</i>, <b>17</b><i>b </i>and <b>17</b><i>c</i>, an ablation catheter of the present invention is illustrated. Ablation catheter <b>180</b><i>b </i>is of similar construction to ablation catheter <b>180</b> of <figref idref="DRAWINGS">FIGS. 12 through 14</figref> with common elements having the same reference numbers. For brevity, most of the common construction and common component details will be omitted. Ablation catheter <b>180</b><i>b </i>includes handle <b>195</b> with operator controls first slide <b>197</b><i>a</i>, second slide <b>197</b><i>b </i>and lever <b>196</b>, each operably attached to a control shaft or other linkage. Plug <b>198</b> is connected to one or more electrical wires or other conduits that travel distally through outer shaft <b>182</b> and connect to one or more functional elements of the device, such as electrodes included in carrier assembly <b>185</b>. The distal end of ablation catheter <b>192</b> includes an atraumatic tip <b>192</b>, preferably constructed of Pebax which has been doped with Barium Sulfate for radiopacity. The ablation catheter <b>180</b><i>b </i>of <figref idref="DRAWINGS">FIG. 17</figref> depicts the carrier assembly <b>185</b> in a fully deployed (maximum diameter) configuration, caused by retracting the control shaft via a slide or lever on handle <b>196</b>.

Referring now to <figref idref="DRAWINGS">FIG. 17</figref><i>a</i>, carrier arm carrier assembly <b>185</b> is in its fully deployed (maximum diameter) condition. Carrier arm <b>186</b> is attached on its distal end to first control shaft <b>184</b>. On its proximal end, instead of being attached to the distal portion of outer shaft <b>182</b> as the ablation device <b>180</b> of <figref idref="DRAWINGS">FIG. 12</figref><i>a</i>, carrier arm <b>186</b> is attached to a second control shaft <b>213</b>, which also can be advanced and retracted from a control on handle <b>195</b>. Advancement and retraction of both first control shaft <b>184</b> and second control shaft <b>213</b> can be used, independently or in combination, to change the geometry of carrier assembly <b>185</b>.

Referring now to <figref idref="DRAWINGS">FIG. 17</figref><i>b</i>, a differentiating feature of ablation catheter <b>180</b><i>b </i>is illustrated where second control shaft <b>213</b> has been retracted until carrier arm <b>186</b>, including ablation elements <b>188</b>, is contained completely within a lumen of outer shaft <b>182</b>, such as within a lumen within a Teflon liner. In an alternative embodiment, carrier arm <b>186</b> is retracted within outer shaft <b>182</b> by retracted first control shaft <b>184</b>.

Referring now to <figref idref="DRAWINGS">FIG. 17</figref><i>c</i>, an end view of the device and deployment status of <figref idref="DRAWINGS">FIG. 17</figref><i>a </i>is illustrated. Carrier arm <b>186</b> is shown in its less than 360° helix. Also shown are electrodes <b>188</b>, typically 2-3 mm in length with symmetric 3 mm spacing between electrodes.

It should be understood that numerous other configurations of the systems, devices and methods described herein can be employed without departing from the spirit or scope of this application. It should be understood that the system includes multiple functional components, such as the ablation catheter and the energy delivery apparatus. The ablation catheter consists of a catheter shaft, a carrier assembly for providing electrodes in a resiliently biased configuration, a control shaft for deploying and withdrawing the carrier assembly, and a coupler for attaching the control shaft to the carrier assembly. The carrier assembly is a support structure which is shiftable from a storage or confined configuration, such as a radially constrained configuration, to a deployed or expanded configuration. The carrier assembly can includes wires, ribbons, cables and struts, made of either metals, non-metals or combinations of both. The carrier assembly can be constructed of one or more materials, including both metals and non-metals. Typical metals chosen for carrier assembly construction include but are not limited to: stainless steel, Nitinol, Elgiloy™, other alloys and combinations thereof.

The ablation catheter of the present invention may include a steerable outer sheath, or may work in conjunction as a system with a separate steerable outer sheath. One or more tubular components of the ablation catheter may be steerable such as with the inclusion of a controllable pull wire at or near the distal end. The ablation catheter of the present invention may be inserted over the wire, such as via a lumen within one of the tubular conduits such as within a lumen of the tubular body member or control shaft, or alternatively the catheter may include a rapid exchange sidecar at or near its distal end, consisting of a small projection with a guidewire lumen therethrough. A guidewire lumen may be included solely for the guidewire, or may provide other functions such as a vacuum lumen for an integral suction port integrated at the distal portion of the carrier assembly.

The ablation catheter of the present invention further includes ablation elements. In preferred embodiments, one or more ablation elements are electrodes configured to deliver RF energy. Other forms of energy, alternative or in addition to RF, may be delivered, including but not limited to: acoustic energy and ultrasound energy; electromagnetic energy such as electrical, magnetic, microwave and radiofrequency energies; thermal energy such as heat and cryogenic energies; chemical energy; light energy such as infrared and visible light energies; mechanical energy; radiation; and combinations thereof. One or more ablation elements may comprise a drug delivery pump or a device to cause mechanical tissue damage such as a forwardly advanceable spike or needle. The ablation elements can deliver energy individually, in combination with or in serial fashion with other ablation elements. The ablation elements can be electrically connected in parallel, in series, individually, or combinations thereof. The ablation catheter may include cooling means to prevent undesired tissue damage and/or blood clotting. The ablation elements may be constructed of various materials, such as plates of metal and coils of wire for RF energy delivery. The electrodes can take on various shapes including shapes used to focus energy such as a horn shape to focus sound energy, and shapes to assist in cooling such as a geometry providing large surface area. Electrodes can vary within a single carrier assembly, such as a spiral array of electrodes or a umbrella tip configuration wherein electrodes farthest from the central axis of the catheter have the largest major axis. Wires and other flexible conduits are attached to the ablation elements, such as electrical energy carrying wires for RF electrodes or ultrasound crystals, and tubes for cryogenic delivery.

The ablation elements requiring electrical energy to ablate require wired connections to an electrical energy power source such as an RF power source. In configurations with large numbers of electrodes, individual pairs of wires for each electrode may be bulky and compromise the cross-sectional profile of the ablation catheter. In an alternative embodiment, one or more electrodes, connected in serial fashion such that a reduced number of wires, such as two wires, can be attached to two or more electrodes, include switching means such that while a first electrode is powered, the remaining electrodes do not transmit ablative energy. Switching means may be a thermal switch, such that as a first electrodes heats up, a single pole double throw switch change state disconnecting power from that electrode and attaching power to the next electrode in the serial connection. This integral temperature switch may have a first temperature to disconnect the electrode, and a second temperature to reconnect the electrode wherein the second temperature is lower than the first temperature, such as a second temperature below body temperature. In an alternative embodiment, each electrode is constructed of materials in their conductive path such that as when the temperature increased and reached a predetermined threshold, the resistance abruptly decreased to near zero, such that power dissipation, or heat, generated by the electrode was also near zero, and more power could be delivered to the next electrode incorporating the above switching means.

The ablation catheter of the present invention preferably includes a handle activating or otherwise controlling one or more functions of the ablation catheter. The handle may include various knobs, such as rotating or sliding knobs which are operably connected to advanceable conduits, or are operably connected to gear trains or cams which are connected to advanceable conduits. These knobs, such as knobs use to deflect a distal portion of a conduit, or to advance or retract the carrier assembly, preferably include a reversible locking mechanism such that a particular tip deflection or deployment amount can be maintained through various manipulations of the system.

The ablation catheter may include one or more sensors, such as sensors used to detect chemical activity; light; electrical activity; pH; temperature; pressure; fluid flow or another physiologic parameter. These sensors can be used to map electrical activity, measure temperature, or gather other information that may be used to modify the ablation procedure. In a preferred embodiment, one or more sensors, such as a mapping electrode, can also be used to ablate tissue.

Numerous components internal to the patient, such as the carrier assembly or electrodes, may include one or more visual markers such as radiopaque markers visible under fluoroscopy, or ultrasound markers.

Selection of the tissue to be ablated may be based on a diagnosis of aberrant conduit or conduits, or based on anatomical location. RF energy may be delivered first, followed by another energy type in the same location, such as when a single electrode can deliver more than one type of energy, such as RF and ultrasound energy. Alternatively or additionally, a first procedure may be performed utilizing one type of energy, followed by a second procedure utilizing a different form of energy. The second procedure may be performed shortly after the first procedure, such as within four hours, or at a later date such as greater than twenty-four hours after the first procedure. Numerous types of tissue can be ablated utilizing the devices, systems and methods of the present invention. For example, the various aspects of the invention have application in procedures for ablating tissue in the prostrate, brain, gall bladder, uterus, other organs and regions of the body, and a tumor, preferably regions with an accessible wall or flat tissue surface. In the preferred embodiment, heart tissue is ablated, such as left atrial tissue.

In another preferred embodiment of the system of the present invention, an ablation catheter and a heat sensing technology are included. The heat sensing technology, includes sensor means that may be placed on the chest of the patient, the esophagus or another area in close enough proximity to the tissue being ablated to directly measure temperature effects of the ablation, such as via a temperature sensor, or indirectly such as through the use of an infrared camera. In the described system, when a temperature or a surrogate temperature reaches a threshold, such as an adjustable threshold, the ablation energy is reduced or stopped, to one or more ablation elements. The threshold will depend on the location of the sensor means, as well as where the ablation energy is being delivered. The threshold may be adjustable, and may be automatically configured.

Numerous kit configurations are also to be considered within the scope of this application. An ablation catheter is provided with multiple carrier assemblies. These carrier assemblies can be removed for the tubular body member of the catheter, or may include multiple tubular body members in the kit. The multiple carrier assemblies can have different patterns, different types or amounts of electrodes, and have numerous other configurations including compatibility with different forms of energy.

Though the ablation device has been described in terms of its preferred endocardial and transcutaneous method of use, the array may be used on the heart during open heart surgery, open chest surgery, or minimally invasive thoracic surgery. Thus, during open chest surgery, a short catheter or cannula carrying the carrier assembly and its electrodes may be inserted into the heart, such as through the left atrial appendage or an incision in the atrium wall, to apply the electrodes to the tissue to be ablated. Also, the carrier assembly and its electrodes may be applied to the epicardial surface of the atrium or other areas of the heart to detect and/or ablate arrhythmogenic foci from outside the heart.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims. In addition, where this application has listed the steps of a method or procedure in a specific order, it may be possible, or even expedient in certain circumstances, to change the order in which some steps are performed, and it is intended that the particular steps of the method or procedure claim set forth herebelow not be construed as being order-specific unless such order specificity is expressly stated in the claim.